Senecio scopolii Hoppe & Hornschuch (1818: 251)

Calvo, Joel, Álvarez, Inés & Aedo, Carlos, 2015, Systematics of Senecio section Crociseris (Compositae, Senecioneae), Phytotaxa 211 (1), pp. 448-450 : 448-450

6. Senecio scopolii Hoppe & Hornschuch (1818: 251) , replacement name. Replaced name: Senecio lanatus Scopoli (1772: 165) , nom. illeg. ( McNeill et al. 2012, ICN Art. 53.1), non Linnaeus (1759: 1216). Cineraria arachnoidea Reichenbach in Mössler (1829: 1501), nom. illeg. superfl. ( McNeill et al. 2012, ICN Art. 52.1). Senecio doronicum var. lanatus Koch (1837: 391) [“lanatam”]. Senecio arachnoideus Sieber ex Candolle (1838a: 357) , nom. illeg. superfl. ( McNeill et al. 2012, ICN Art. 52.1). Senecio lanatus var. arachnoideus Nyman (1879: 355) . Senecio doronicum var. arachnoideus (Nyman) Fiori (1903: 218) . TYPE: Italy, Triest, Karstwiesen am Monte Spaccato, [45º39'N 13º49'E], June 1891, K. Steurer s.n. (neotype, designated here, B-10-0299795!; isotypes B-10-0299794!, LE!, P-3688121 image!).

Perennial herb. Rhizome 1.5–4 cm long, 0.3–0.6 cm in diam., ± horizontal, with swelled fastigiate roots. Stem 17–64 cm, erect, leaved to almost bared, corrugated, solid, not ramificated, arachnoid to covered with scattered arachnoid trichomes, sometimes lanate towards base and under the capitula, base without remnants of old leaves or tufts of hairs. Basal leaves 3.9–10.8 cm long, 1.6–4.4 cm wide, persistent, lanceolate to obovate (ratio basal leaf width / basal leaf length = 0.29–0.68), obtuse, attenuate to rounded, with a petiole 1.5–10.5 cm long, irregularly dentate, often ± crenate (teeth 0.4–1.5 mm deep), glabrescent to weakly arachnoid above, ± arachnoid to covered with scattered arachnoid trichomes beneath (trichomes ca. 0.7 mm long), concolorous. Cauline leaves 3–12; middle cauline leaves 2.3–18.2 cm long, 0.2–3.3 cm wide, alternate, lanceolate (ratio middle leaf width / middle leaf length = 0.09–0.37), acute, sessile to semi-amplexicaul, sometimes attenuated into a petiole up to 5 cm long, dentate to subentire (teeth 0.6–1.5 mm deep), glabrescent to weakly arachnoid above, ± arachnoid to covered with scattered arachnoid trichomes beneath, tertiary venation inconspicuous; upper cauline leaves 1–5.7 cm long, 0.1–0.8 cm wide, oblong to narrowly lanceolate (ratio upper leaf width / upper leaf length = 0.04–0.24), acute, sessile to semi-amplexicaul auriculate, entire to subentire, ± arachnoid. Synflorescence reduced to a solitary capitulum, rarely pseudocorymbose, 7.5–13 cm long, with scarce linear-oblong bracts. Capitula 1(–3), 29.3–55.2 mm in diam.; involucre 11.8–29.4 mm in diam., 12–18 mm long, cupuliform; involucral bracts (18–)28–32(–34), 6.2–15.3 mm long, 1–2.1 mm wide, with scarious margin 0.2–0.6 mm wide, lanceolate to oblong, long-attenuate, smooth, apex usually without a black spot, ± lanate to covered with scattered arachnoid trichomes (trichomes 0.3–1.3 mm long); supplementary bracts (8–)14–26(–44), 6.9–15.2 mm long, 0.6–1.7 mm wide, long-subulate, slightly scarious on the margin, three quarters as long as involucral bracts to slightly longer, lanate to covered with scattered arachnoid trichomes (trichomes 0.1–1.6 mm long), ± imbricated. Ligulate florets 13–32, 14.7–27.6 mm long, pale yellow; tubular florets 5.7–9.7 mm long, 0.7–1.5 mm in diam., pale yellow. Achenes 4.2–6.7 mm long, 0.9–1.3 mm wide, subcylindrical (ratio achene width / achene length = 0.16–0.28), shorter than pappus (ratio achene length / pappus length = 0.58–0.75), with 10–12 ribs, glabrous to covered with scattered intercostal trichomes ca. 0.1 mm long; pappus 8–9 mm long, whitish.

Etymology: — Senecio scopolii is named in honor of Giovanni Antonio Scopoli (1723–1788), Austrian-Italian (Tirol-born) physician, chemist and botanist.

Discussion: — Senecio scopolii is characterized by its solitary capitulum, very rarely up to 3, and its arachnoid-lanate involucre with supplementary bracts as long as the involucral ones, often longer, usually without black spot at the summit, and sometimes ± imbricated. This taxon presents a circum-Adriatic distribution, and is highly variable concerning the indumentum of capitula, number of supplementary bracts, and the shape, consistency, and indumentum of leaves. Most populations display lanceolate to oblanceolate leaves, thin, glabrescent above, and

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CALVO ET AL.

arachnoid to weakly arachnoid beneath, whereas the populations from Abruzzo and Marche (Apennine Mountains) usually have obovate leaves, subcoriaceous, with scabrid-arachnoid trichomes on both faces. On this basis, we recognize two subspecies. The species similar to S. scopolii are S. doronicum and S. eriopus . Their differences are discussed under the respective species.

According to Staffleu & Cowan (1985: 453), the collections of Scopoli are at LINN (a set received by Linnaeus), C (through Vahl), UPS (in herb. Thunberg), B (mainly destroyed), MPU (through Lapeyrouse). Our efforts to locate the original material were unsuccessful, thus, we neotypify S. scopolii with a Steurer’s collection from nearby the locus classicus.